JP2006292137A - Flow control valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flow control valve capable of allowing fluid to easily flow by reducing flow channel resistance, stabilizing the flow of fluid, accurately changing valve opening at a high speed, improving responsiveness in valve opening and closing operation, and elongating its service life. <P>SOLUTION: This flow control valve wherein a flow channel inlet port 16, a valve element 21, a linear converting mechanism and a flow channel outlet port 17 are linearly mounted, has a ball screw nut 27 for transmitting rotary drive of a servomotor 31, the linear converting mechanism comprising a ball screw 23 for converting the rotary drive into linear drive and a ball screw spindle 26 having a spline for transmitting the linear drive, and the valve element 21 integrated with the ball screw spindle 26 and moved in parallel with the axial direction of the flow channel inlet portion1 16 and the flow channel outlet port 17. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a flow control valve that controls, for example, a vacuum pressure.

As background art, the following flow control valve exists as an invention of Patent Document 1.
FIG. 4 is a cross-sectional view of the flow path opening / closing valve 101 of the invention of Patent Document 1, showing the valve closed state. The flow path opening / closing valve 101 has an outer shape formed by a valve housing 111. The valve housing 111 has flange portions 112 and 113 at both ends, and a fluid flow path 114 is formed between the flange portions 112 and 113. Is formed. When the drive shaft 115 is rotated in the L direction from the valve closed state shown in FIG. 4, the valve body 117 is lifted away from the valve seat 118 by the tensile force of the spring 116. Further, when the drive shaft 115 is rotated in the L direction, the valve body 117 turns around the connection point A, and the valve body disk portion 119 substantially overlaps the pipe portion centerline shaft 120 as shown in FIG. Thus, the valve opening degree of the flow path opening / closing valve 101 is maximized.

  FIG. 6 shows a cross-sectional view of the flow control valve 201 of the invention of Patent Document 2. In the flow rate control valve 201, a flow path port 212, a hole 214 of a valve seat 213, a valve chamber 215, and a flow path port 212 are communicated with each other in a valve body 211 to form a flow path 216. Further, a stepping motor 221 is arranged in the drive system, and the rotational driving force of the stepping motor 221 is converted into a linear driving force by the eccentric cam 222, and the valve body 217 is controlled via the valve body operating member 223. Thus, valve opening and valve closing operations are performed.

Further, in the conventional air cylinder type direct acting valve, a driving force is applied to the valve element by the air cylinder in order to perform valve opening and valve closing operations.
JP 10-196806 (paragraphs 0034 and 0035, FIG. 1) JP 2002-168361 (paragraphs 0019, 0025, FIG. 1)

  However, in the flow path opening / closing valve 101 of Patent Document 1, since the opening / closing operation of the valve is performed by rotating the first link 121, the second link 122, and the third link 123, it takes time to open and close the valve. The valve opening cannot be set accurately. In addition, the fluid flows along the fluid flow path 114 formed between the flange portions 112 and 113. However, the rotating operation of the valve disc portion 119 is performed against the flow of the fluid, so that a retention portion or the like is present in the fluid. This may cause the fluid flow to become unstable.

  Further, in the flow control valve 201 of Patent Document 2 and the conventional air cylinder type direct acting valve, the flow path between the flow path port 212 and the flow path port 218 is formed in a right angle. For this reason, a fluid retention portion is likely to be generated, and the flow path resistance is increased and the fluid is difficult to flow.

  Further, in the flow control valve 201 of Patent Document 2, the rotational driving force of the stepping motor 221 is converted into a linear driving force by the eccentric cam 222. However, since the eccentric cam 222 is likely to slip during conversion of the driving force, it takes a lot of time to perform accurate positioning, and it is difficult to accurately vary the valve opening at high speed. Moreover, the attachment part of the stepping motor 221 becomes large, and the flow control valve becomes large.

  In the conventional air cylinder type direct acting valve, a driving force is applied to the valve element by the air cylinder in order to perform valve opening and valve closing operations. Therefore, the responsiveness of the valve opening and valve closing operations becomes lower than when driven by a motor. In addition, the life of the cylinder piston portion is shortened because the seal member is in contact with the cylinder piston portion.

  Here, a vacuum control valve connected to a vacuum chamber used in a semiconductor production line or the like is considered. In a vacuum control valve connected to a vacuum chamber used in a semiconductor manufacturing line or the like, it is desired that no fluid stays in the vacuum control valve in order to ensure a vacuum in the vacuum chamber. Further, in order to accurately control the pressure in the chamber directly connected to the flow path inlet port with high responsiveness, it is desired that the valve opening of the vacuum control valve be accurately varied at high speed. Furthermore, due to the frequent frequency of valve opening and closing operations, it is desired to increase the durability of the vacuum control valve and extend its life.

  Therefore, the present invention can reduce the flow path resistance to facilitate fluid flow, stabilize the fluid flow, change to a high-speed and accurate valve opening, and open and close the valve. An object of the present invention is to provide a flow rate control valve that can increase the responsiveness of the operation and can extend the life.

In order to achieve the above object, the present invention has the following features.
(1) In the flow control valve in which the first port, the valve body, the linear conversion mechanism, and the second port are arranged on a straight line, the present invention converts the nut and the rotational drive that transmit the rotational drive of the servo motor into the linear drive. A linear conversion mechanism including a ball screw that rotates and a main shaft on which a spline that transmits linear driving is formed, and a valve body that is translated in the direction of the central axis of the first port and the second port and is integral with the main shaft. It is characterized by having.

(2) The present invention provides the flow rate control valve according to (1), a support member disposed on the inner peripheral surface side of the substantially cylindrical cover portion, a substantially cylindrical bracket attached to the support member, and a bracket A ball screw disposed on the inner peripheral surface side, a main shaft disposed on the inner peripheral surface side of the ball screw, and a valve body disposed on an end portion of the main shaft opposite to the ball screw. To do.

(3) According to the present invention, in the flow control valve described in (1) or (2), a servo motor disposed on the outer peripheral surface side of the substantially cylindrical cover portion, and the servo motor is integrated with the second port. A first pulley disposed on the side, a second pulley disposed integrally with the ball screw nut constituting the ball screw and disposed on the second port side, and a timing belt connecting the first pulley and the second pulley. It is characterized by having.

(4) According to the present invention, in any one of the flow control valves described in (1) to (3), when the valve is opened from the valve open state, the valve body is pressed against the valve seat by the driving force of the motor. The servo motor is stopped when the torque value of the motor reaches a predetermined value.

The present invention having such characteristics has the following operations and effects.
(1) In the flow control valve in which the first port, the valve body, the linear conversion mechanism, and the second port are arranged on a straight line, the present invention converts the nut and the rotational drive that transmit the rotational drive of the servo motor into the linear drive. A linear conversion mechanism including a ball screw that rotates and a main shaft on which a spline that transmits linear driving is formed, and a valve body that is translated in the direction of the central axis of the first port and the second port and is integral with the main shaft. Therefore, since the flow path is formed in a straight line, the flow resistance can be reduced to facilitate the flow of the fluid, and the valve body moves in parallel with the flow of the fluid, thereby stabilizing the flow of the fluid. The drive of the servo motor is accurately transmitted to the valve body by the signal of the built-in encoder, so that the valve opening can be changed at high speed and accurately, and the valve can be opened by the high speed drive of the servo motor. In addition, the responsiveness of the valve closing operation can be increased, and the drive of the servo motor is transmitted to the valve body by the main shaft formed with the ball screw and the spline, so the durability of the drive mechanism is high and the life is extended. The effect that can be obtained.

(2) The present invention provides the flow rate control valve according to (1), a support member disposed on the inner peripheral surface side of the substantially cylindrical cover portion, a substantially cylindrical bracket attached to the support member, and a bracket Since the ball screw is disposed on the inner peripheral surface side, the main shaft is disposed on the inner peripheral surface side of the ball screw, and the valve body is disposed on the end of the main shaft opposite to the ball screw. In addition to the effects described in (1), the flow of the fluid can be stabilized because each component is arranged in parallel to the fluid flow direction.

(3) According to the present invention, in the flow control valve described in (1) or (2), a servo motor disposed on the outer peripheral surface side of the substantially cylindrical cover portion, and the servo motor is integrated with the second port. A first pulley disposed on the side, a second pulley disposed integrally with the ball screw nut constituting the ball screw and disposed on the second port side, and a timing belt connecting the first pulley and the second pulley. Therefore, in addition to the effects described in (1) or (2), the fluid control valve can be miniaturized by making the mounting of the servomotor compact.

(4) In the flow control valve according to any one of (1) to (3), the valve body is pressed against the valve seat by the driving force of the servo motor when the valve is opened to the valve closed state. Since the servo motor is stopped when the torque value of the servo motor reaches a predetermined value, in addition to the effects described in (1) to (3), an unnecessary load is not applied to the seal member, and the valve mechanism portion The effect which can lengthen a lifetime is acquired.

  Examples of the present invention will be described below. In this embodiment, a vacuum pressure control valve among the fluid control valves will be described. FIG. 1 is a sectional view of a vacuum pressure control valve 1 according to the present invention, showing a valve closed state. As shown in FIG. 1, the vacuum pressure control valve 1 has an outer shape formed by a flange body 11, an in-line body 12 as a substantially cylindrical cover portion, and a motor flange 13. A flow path 14 is formed on the inner peripheral side of the inline body 12. And the flow path 13a is formed also in the inner peripheral side of the motor flange 13 like FIG. Here, FIG. 3 is an AA cross-sectional view shown in FIG.

  The internal configuration of the vacuum pressure control valve 1 can be broadly divided into a valve mechanism portion and a drive mechanism portion. As shown in FIG. 1, the valve mechanism includes a flow path inlet port 16, a flow path outlet port 17, a valve body 21, a bellows 22, a ball screw 23, a holder 24, a ball screw main shaft 26, a ball screw nut 27, a seal member. 28, valve seat 29, and the like. The ball screw 23 is disposed on the inner peripheral side of a holder 24 that is a substantially cylindrical bracket, and the holder 24 is coupled by a bolt at a bolt hole 36a of a center flange 36 that is a support member. As shown in FIG. 7, a flow path 36 b is formed in the center flange 36 and is sandwiched between the in-line body 12 and the motor flange 13 and held firmly. A ball screw main shaft 26 is disposed on the inner peripheral surface side of the ball screw 23. The bellows 22 integral with the valve body 21 and the holder 24 is arranged so as to cover the outer periphery of the ball screw main shaft 26. The bellows 22 can freely expand and contract in the direction of the axis 15, insulates the flow path 14 and the ball screw 23, so that outside air does not enter the flow path 14 even when vacuumed. A valve body 21 is coupled to the end of the ball screw main shaft 26 opposite to the ball screw 23. A large pulley 33 described later is coupled to a ball screw nut 27 disposed on the flow path outlet port 17 side of the ball screw 23. Further, a seal member 28 is disposed at the end of the valve body 21. Thus, each component is arranged between the flow path inlet port 16 and the flow path outlet port 17 in parallel with the fluid flow direction.

  On the other hand, as shown in FIG. 1, the drive mechanism section includes a servo motor 31, a timing belt 32, a large pulley 33, a small pulley 34, and the like. The servo motor 31 is disposed on the outer peripheral surface side of the inline body 12 and the motor flange 13. A small pulley 34 is coupled to the flow path outlet port 17 side of the servo motor 31, and the large pulley 33 is coupled to the ball screw nut 27 disposed on the flow path outlet port 17 side of the ball screw 23 as described above. Has been. The large pulley 33 and the small pulley 34 are connected by a timing belt 32. The timing belt outlet 25 where the timing belt 32 is disposed is isolated from the flow path 14 by the motor flange 13 having a cross section as shown in FIG. The position of the valve body 21 can be grasped by calculating the signal of the encoder 35 built in the servo motor 31.

  The vacuum pressure control valve 1 having such a configuration operates as follows. In order to change the valve closed state of FIG. 1 to the valve open state, first, the servo motor 31 is rotated. Then, the ball screw nut 27 connected by the timing belt 32 rotates, and the ball screw main shaft 26 is translated in the direction of the axis 15 toward the drive mechanism section. Then, the valve body 21 integrated with the ball screw main shaft 26 is separated from the valve seat 29. At this time, the opening area of the flow path inlet port 16 can be adjusted by changing the distance between the valve body 21 and the valve seat 29. Thereby, the flow rate and pressure of the fluid can be changed and adjusted, and as a result, the pressure in a chamber (not shown) directly connected to the flow path inlet port 16 is controlled.

  On the other hand, when changing from the valve open state to the valve closed state, the servo motor 31 is rotated in the opposite direction to the above case. Then, the ball screw nut 27 connected by the timing belt 32 rotates in the opposite direction to the above case, and the ball screw main shaft 26 moves in the direction opposite to the above case in the direction of the axis 15. Then, the valve body 21 is pressed against the valve seat 29, and the servo motor 31 is stopped when the torque value of the servo motor 31 reaches a predetermined value. At this time, by using a motor with a brake as the servo motor 31, the torque value by the servo motor 31 can be maintained at a predetermined value. Even when a motor without a brake is used, by outputting an arbitrary torque value from the servo motor 31, the torque value by the servo motor 31 can be maintained at a predetermined value. Here, the predetermined value of the torque value by the servo motor 31 is arbitrarily set, and the seal member 28 and the valve seat correspond to the degree of vacuum in the flow path inlet port 16 and the flow path 14. 29 is a value that can achieve the necessary sealing force with the 29.

  Thus, in the vacuum pressure control valve 1 of the present invention, the ball screw nut 27 is rotated by using the servo motor 31 as a driving source, and the ball screw main shaft 26 in which a spline is formed is driven via the ball screw 23. Then, the valve is opened and closed. Therefore, the responsiveness of the valve opening and valve closing operations can be enhanced by the high speed driving of the servo motor 31. Further, since the moving amount of the valve body 21 can be accurately adjusted by the encoder 35 incorporated in the servo motor 31, the valve opening degree can be set accurately. Therefore, the pressure in the chamber (not shown) directly connected to the flow path inlet port 16 can be accurately controlled with high responsiveness. Furthermore, since the drive torque can be minimized by using the ball screw 23 or the ball screw main shaft 26 formed with splines as the drive transmission mechanism of the servo motor 31, an extra load is applied to the valve mechanism. However, the durability can be increased. Further, since the servo motor 31 is disposed compactly on the outer peripheral surface side of the in-line body 12 and the motor flange 13, the flow control valve can be reduced in size.

  Further, as shown in FIG. 1 and FIG. 2, since the flow path inlet port 16 and the flow path outlet port 17 are on the same axis, the fluid retention portion is reduced, the flow resistance is reduced, and the fluid flows easily. Become. Further, since the valve body 21 moves back and forth on the same axis between the flow path inlet port 16 and the flow path outlet port 17, it operates along the direction of fluid flow. Therefore, the flow of the fluid is not blocked and no fluid retention portion is generated, so that the fluid easily flows. Furthermore, each component of the valve mechanism is disposed between the flow path inlet port 16 and the flow path outlet port 17 in parallel with the fluid flow direction, so that the fluid flows into the flow path inlet port 16 when the valve is opened. From the valve body 21 to the flow path outlet port 17 through the flow path 14, the flow path 36b of the center flange 36, and the flow path 13a of the motor flange 13. Therefore, a fluid staying portion does not occur in the vacuum pressure control valve 1, and the fluid easily flows. Since the fluid easily flows in this way, the relationship between the valve opening and the flow rate is stabilized, the pressure in the chamber (not shown) directly connected to the flow path inlet port 16 can be accurately controlled, and the vacuum is surely obtained. It can also be.

  Furthermore, in the vacuum pressure control valve 1 of the present invention, the valve body 21 is driven using only the servo motor 31 as a drive source. Therefore, the sealing force applied from the valve element 21 to the sealing member 28 when the valve is closed is only the driving force of the servo motor 31. Therefore, since the sealing force more than necessary is not applied to the sealing member 28, the sealing member 28 is not likely to be permanently deformed even when the valve is closed for a long time. Therefore, the durability of the vacuum pressure control valve 1 can be improved.

The following effects are obtained by the embodiment as described above.
(1) The present invention provides a ball screw that transmits the rotational drive of a servo motor 31 in a vacuum pressure control valve in which a flow path inlet port 16, a valve body 21, a linear conversion mechanism, and a flow path outlet port 17 are arranged in a straight line. A linear conversion mechanism including a nut 27, a ball screw 23 for converting rotational drive to linear drive, and a ball screw main shaft 26 on which a spline for transmitting linear drive is formed, and the centers of the flow path inlet port 16 and the flow path outlet port 17 Since the ball screw main shaft 26 and the integral valve body 21 are moved in parallel in the axial direction, the flow path is formed in a straight line, so that the flow resistance is reduced and the fluid flows easily. Since the valve body 21 moves parallel to the fluid flow, the fluid flow can be stabilized, and the servo motor 31 is driven by a signal from the built-in encoder 35. Since it is accurately transmitted to the valve body 21, the valve opening can be changed to an accurate valve opening speed, and the responsiveness of the valve opening and closing operations can be increased by the high speed driving of the servo motor 31, The drive of the servo motor 31 is transmitted to the valve body 21 by the ball screw main shaft 26 formed with the ball screw 23 and the spline, so that the durability of the drive mechanism portion is increased and the life can be extended.

(2) The present invention is the vacuum pressure control valve described in (1), wherein the substantially cylindrical inline body 12 and the center flange 36 disposed on the inner peripheral surface side of the motor flange 13 are attached to the center flange 36. A substantially cylindrical holder 24, a ball screw 23 disposed on the inner peripheral surface side of the holder 24, a main shaft 26 disposed on the inner peripheral surface side of the ball screw 23, and a main shaft 26 opposite to the ball screw 23. In addition to the effect described in (1), the flow of fluid can be stabilized because each component is arranged in parallel to the flow of fluid. .

(3) In the vacuum pressure control valve described in (1) or (2), the present invention provides a servo motor 31 disposed on the outer peripheral surface side of the substantially cylindrical inline body 12 and the motor flange 13, and the servo motor 31. A small pulley 34 that is integral with the flow path outlet port 17, a large pulley 33 that is integral with the ball screw nut 27 constituting the ball screw 23 and disposed on the flow path outlet port 17 side, Since the timing belt 32 for connecting the small pulley 34 and the large pulley 33 is provided, in addition to the effect described in (1) or (2), the mounting of the servo motor 31 is made compact so that the fluid control valve is downsized. can do.

(4) According to the present invention, in the vacuum pressure control valve described in (1) to (3), the valve body 21 is pressed against the valve seat 29 by the driving force of the servo motor 31 when the valve is opened to the valve closed state. Since the servo motor 31 is stopped when the torque value of the servo motor 31 reaches a predetermined value, in addition to the effect described in (1), the seal member 28 is not subjected to an excessive load, and the life of the valve mechanism section is reached. The effect which can lengthen is acquired.

In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning. In this embodiment, the vacuum pressure control valve has been described, but the present invention can also be applied to a chemical liquid control valve, an air pressure control valve, and the like. In this embodiment, a servo motor is used, but a stepping motor may be used. Furthermore, in this embodiment, a timing belt is used, but a gear train may be used.

It is sectional drawing (valve closed state) of the vacuum pressure control valve 1 of this invention. It is sectional drawing (valve open state) of the vacuum pressure control valve 1 of this invention. It is AA sectional drawing in FIG. It is sectional drawing (valve closed state) of the flow-path opening-and-closing valve of patent documents 1. It is sectional drawing (valve open state) of the flow-path opening-and-closing valve of patent documents 1. 6 is a cross-sectional view of a flow rate control valve of Patent Document 2. FIG. It is an external view of the center flange in the vacuum pressure control valve 1 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vacuum pressure control valve 11 Flange body 12 In-line body 13 Motor flange 21 Valve body 22 Bellows 23 Ball screw 24 Holder 26 Ball screw spindle 27 Ball screw nut 31 Servo motor 32 Timing belt 33 Large pulley 34 Small pulley 35 Encoder

Claims (4)

In the flow control valve in which the first port, the valve body, the linear conversion mechanism, and the second port are arranged on a straight line,
A linear conversion mechanism comprising a nut that transmits the rotational drive of a servo motor, a ball screw that converts the rotational drive into a linear drive, and a main shaft on which a spline that transmits the linear drive is formed;
A valve body that translates in the direction of the central axis of the first port and the second port and is integral with the main shaft;
A flow control valve characterized by comprising: In the flow control valve according to claim 1,
A support member disposed on the inner peripheral surface side of the substantially cylindrical cover portion, a substantially cylindrical bracket attached to the support member, the ball screw disposed on the inner peripheral surface side of the bracket, and the ball A flow control valve comprising: the main shaft disposed on an inner peripheral surface side of the screw; and a valve body disposed on an end portion of the main shaft opposite to the ball screw. In the flow control valve according to claim 1 or 2,
A servo motor disposed on the outer peripheral surface side of the substantially cylindrical cover portion, a first pulley integral with the servo motor and disposed on the second port side, and a ball screw nut constituting the ball screw; A flow rate control valve comprising: a second pulley that is integrated and disposed on the second port side; and a timing belt that connects the first pulley and the second pulley. The flow control valve according to any one of claims 1 to 3,
A flow rate control characterized in that when the valve is opened from the valve open state, the valve body is pressed against the valve seat by the driving force of the motor, and the servo motor is stopped when the torque value of the servo motor reaches a predetermined value. valve.

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